Refrigeration



March 23,11937. w. KlLLl-QN REFRIGERATION Filed Jan. 14, 1923 PatentedMar. 23, 1937 PATENT oFElcE y REFRIGERATION James It. Kiilen, Dayton,Ohio, assignor, by mesne assignments, to General Motors Corporation, acorporation of Delaware Application January 14, 1.933, Serial No.651,770

4 olai'ms.

This invention relates to refrigeration.

In certain types of refrigerating apparatus, it is often desirable ornecessary to heat periodically the object being cooled far above thenormal op- 3 erating temperatures. For example, in ice cream freezers,it is often desirable 'or necessary to introduce a quantity of hot waterinto the freezing chamber to clean the same. Also in certain types ofliquid coolers, where a beverage or the like is being cooled, it isoften desirable or necessary to' shut off the beverage supply andintroduce into the beverage cooling chamber or pipe a quantity of hotwater to clean the same.

It is among the objects of this invention to pro- I vide a refrigeratingapparatus or method capable of permitting the introduction of a heating.or washing medium into the objector chamber being cooled Without dangerof injuring the refrigerating apparatus and without the necessity ofstopping the refrigerating mechanism.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred form of the present invention is clearlyshown.

AIn the drawing:

Fig. 1 is a diagrammatic representation of one form of my invention;

Fig. 2 isa diagrammatic representation of a .slightly modied form; and

Fig. 3 is a diagrammatic representation of a further modification.

In the embodiment shown in Fig. 1, the object to be cooled is shown asan ice cream freezer 3 which is provided with a freezing chamber I0having the usual dasher Il operated by a motor I2.- The chamber I0 iscylindrical in form and provided with 4a removable cover I3 having avalved filling funnel or fitting I4. Chamber I0 is also provided with adischarge spout I5 having a valved opening I6 as is usual in this typeof apparatus. The refrigerating system cooperating with the freezerincludes a refrigerant liquefying unit 2li wherein refrigerant' isliquefied and from which liquefied refrigerant is discharged through anautomatic expansion valve 2| into the evaporator or .evaporating zone22, from whence the evaporated refrigerant returns through the pipe 23to the liquefying unit 20 to be reliquefied. In this particular 'formthe refrigerant liquefying unit includes a compressor 24 driven by am'otor 25. The compressed refrigerant from the com- .pressor 24 isdischarged into the condenser 26 which discharges into a liquidrefrigerant re- 55'ceiver 21. Liquid refrigerant flows from the receiver21 through the liquid refrigerant line 28 to the expansion valve 2l andfrom thence the expanded refrigerant ows through the connection 29 tothe evaporator '22. Sometimes the liquefying unit 20 is also connectedto some other apparatus such as an ice cream hardening tank or the like,and, under such conditions, the liquid refrigerant line 28 may beprovided with a branch 30 connected by means of a two-way valve 3l whichis manuallyoperated and can be operated to direct the liquid refrigeranteither to the evaporator 22 or to the other apparatus, such as theevaporator of the hardening tank. The evaporated refrigerant from theevaporator of the other apparatus or hardening tank returns through thebranch 32 to the lline 23. It is `to be understood that if the capacityof the unit 20 is sufficiently large, the two-way valve 3l may bedispensed with and liquid refrigerant may be supplied as required toeither or both the freezer I0 and to the other apparatus as required.

The refrigerant liquefying unit 20 may be automatically controlledinaccordance with conditions in some part of the apparatus, and in thisparticular vembodiment it is controlled by means of a thermostatic bulb33 which in turn operates a snap switch 35 which starts and stops themotor 25. Here also, the automatic control may be connected to thehardening tank heretofore referred to or to any other part of theapparatus desired.

As indicated in Fig. 1, the bulb 33 may be placed adjacent the outletend of the coil or evaporator 22, just outside the freezer chamber I0.The casing of the freezer chamber is indicated in elevation in the upperAportion with the coil 22 wrapped around the casing, and is shown incross section in the lower half. The change from elevation tocross-section is indicated by the irregular substantially horizontalline just above the lead line of the character l0.

When the freezing chamber I0 is abnormally heated, such as by theintroduction of hot Water through the funnel I4 or by pouring afterremoval of cover I3, for the purpose of cleaning, the pressure of theliquid refrigerant in the coil or evaporator 22 is increased above apredetermined limit, and, in order vto prevent the overloading of theunit 20, which ordinarily may be permitted to continue to operate, thereis provided a reser"oir connected by means of the pipe 4I with the lowerportion of 'the evaporator or coil 22 and which forms a gas trapping,liquid refrigerant storage space. The reservoir 40 is constructed to,trap the gas formed by evaporation of refrigerant therein and thereservoir 40 Cal is placed in an environment where it will be maintainedat a temperature above the normal operating temperature of theevaporator 22, but where it will be below the temperature created whenthe freezer I is subjected to the abnormal heating operation. Thus thereservoir 40 may be placed in the normal atmosphere outside theinsulation 42 which surrounds the evaporator 22 and the chamber I0.

The valve 2| admits refrigerant into the evaporator 22 automatically andinversely in accordance with the refrigerant pressure in the evaporator22, and substantially stops the flow of refrigerant when the pressurerises above Aa predetermined limit. 'Ihus when the hot water islintroduced into the chamber I8, the refrigerant pressure in theevaporator 22 rises above this predetermined limit because of theabnormal evaporation of liquid refrigerant at a faster rate than can beliquefied by the liquefying unit. This rise in pressure causes valve 2ito stop the flow of liquid refrigerant into the evaporator 22. 'I'heliquid refrigerant already in the evaporator 22 is forced through. thepipe 4| into the reser- Voir 40 which is now at a lower temperature thanthe refrigerant in evaporator 22 and WhereI the refrigerant remains at apressure lower than in the evaporator, the pressure in reservoir 40corresponding substantially to the refrigerant vapor pressure atatmospheric temperature. When the hot water is removed through thespout-"I or chilled, the evaporation of the slight amount of liquidrefrigerant remaining in the evaporator 22 becomes slower and permitsthe liquefying unit to reduce the pressure in the evaporator graduallyuntil it falls below the pressure prevailing in the reservoir 40. Whenthis occurs, the vapor pressure in the reservoir 40 forces the liquidrefrigerant in the reservoir back into the evaporator 22 and theapparatus resumes its normal operation.

In the modification shown in Fig. 2, avcylindrical ice creamfreezingchamber is shown at by the motor 52.

chamber 50.

50, and, in this modification it is horizontally disposed and has ahorizontal dasher 5| driven The evaporating 53 is in the form of anannular chamber surrounding the Thefreezer is provided with a removablecover 54 having an intake connection 55 and a discharge spout 56. Liquidrefrigerant from a refrigerant liquefying unit similar to 2|), isdischarged through the line5|a through the automatic expansion valve 51,similar to the valve 2|, from whence the expanded refrigerant flowsthroughthe pipe 58 to the evaporator 53. The evaporated refrigerant owsthrough the line 59 to the refrigerant liquefying unit where therefrigerant is reliquefied for re-use in the system. When hot water isintroduced through connection 55, the refrigerant pressure in evaporator53 rises and the liquid refrigerant is forced through the pipe 60 intoreservoir 6| similar to the reservoir 40 where the liquid refrigerantremains until the hot water is withdrawn or is cooled in a mannersimilar to the operation heretofore described with respect to Fig. 1.Here also, the refrigerant liquefying unit may be connected byconnections 62 and 63 with some other apparatus such as theY evaporatorof an ice cream hardening 'tank and the refrigerant liquefying unit maybe automatically controlled by the thermostatic bulb 64 operatingsimilarly to the bulb 33 shown in Fig. 1.

In the modification shown in Fig. 3, the apparatus may be substantiallythe same as in Fig.- 1,

with the exceptionthat the valve is made normally responsiveto athermostatic bulb 1| placed at or near the outlet of the evaporator 13.Liquid refrigerant is received from the liquefying unit through the line14 and returns to the unit through the line 15. Connections t0 thehardening tank or the like may be provided at 16 and 11. During normaloperation, the thermostatic bulb 1| causes the valve 10 to admitsufficient liquid refrigerant into the evaporator 13 until the bulb 1|is cooled to a predetermined limit after which the liquid refrigerantwill be stopped or throttled to maintain a normal liquid refrigerantlevelor condition in the evaporator 13. When hot water is introducedthrough the intake 18, the pressure rises in the evaporator 13 above apredetermined limit where the pressure acting on the diaphragm in valve10 overcomes the pressure from the bulb 1| and stops the ow of liquidrefrigerant through valve 1|] into the evaporator 13. The liquidrefrigerant in the evaporator 13 is forced through the line 19 into thereservoir 80 similar to the reservoir 40 heretofore described withrespect toFig. lwhere liquid refrigerant remains until the hot water is,discharged or cooled in the freezing chamber 8|.

bellows 83 which operates the snap switch 84 which controls a motorsimilar to motor 25 shown in Fig. 1.

This application is a continuation in part of my copending applicationSerial No. 636,540 filed October 6, 1932, for refrigerating apparatus.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming Within the scope of the claims whichfollow.

What is claimed is as follows:

v1. A refrigerating apparatus comprising a refrigerant liquefyingunit,an evaporator receiving liquid refrigerant from said unit anddischarging evaporated refrigerant into said unit, an automaticexpansion valve between said unit and evaporator said valve throttlingthe ow of refrigerant into said evaporator from said unit with the risein refrigerant pressure in said evaporator and stopping the iiow ofrefrigerant from 'said unit into said evaporator when the refrigerantpressure in said evaporator rises above apredetermined limit, saidrefrigerant liquefying unit being automatically controlled in accordancewith conditions in the apparatus and a reservoir connected to the lowerportion of said evaporator, said reservoir having means for trappingevaporator liquid refrigerant therein.

2. A refrigerating apparatus comprising a rel frigerant liquefying unit,an evaporator receiving'liquid refrigerant from said unit anddischarging evaporated refrigerant into said unit, an automaticexpansion valve between said unit and evaporator said valve throttlingthe ow of refrigerant into said evaporator from said unit with the risein refrigerant pressure in said trapping evaporated liquid refrigeranttherein.

3. A refrigerating apparatus comprising a refrigerant liquefying unit,an evaporator receivving liquid refrigerant from; said unit anddischarging evaporated refrigerant into said unit, an expansion valvebetween said unit and evaporatorl said valve controlling the flow ofrefrigerant into said evaporator from said unit in accordance withrefrigerant pressure in said evaporator, a thermostatic bulb in thermalcontact with the refrigerant in said evaporator controlling theeffective normal liquid refrigerant level in said evaporator and areservoir connected to the lower portion of said evaporator, said resyvalve between said condenser and evaporator, said expansion valveautomatically closing as the pressure of the refrigerant in saidevaporator rises above a Apredetermined limit, an electric motor drivingsaid compressor, a thermostat in thermal contact with said evaporatoradjacent its outlet end, said thermostat automatically starting saidmotor when the temperature'rises above a predetermined limit andstopping said motor below a predetermined limit, a closed refrigerantreservoir away from the cooling environment of said evaporator andconnected to the lower end of said evaporator, whereby said motor andcompressor automatically continue to operate, said valve automaticallycloses and said evaporator automatically empties into said reservoirwhen said evaporator is heated abnormally.

JAMES n KILLEN.

